to attack someone (especially verbally) unfairly in a deceitful, underhand, or treacherous manner, especially when they're not present in the place or situation that it happens. (as if stabbing them in the back). See backbite.
To deliver into the hands of an enemy by treachery or fraud, in violation of trust; to give up treacherously or faithlessly.
To violate the confidence of, by disclosing a secret, or that which one is bound in honor not to make known.
To prove faithless or treacherous to, as to a trust or one who trusts; to be false to; to deceive.
To disclose or indicate, for example something which prudence would conceal; to reveal unintentionally.
To mislead; to expose to inconvenience not foreseen; to lead into error or sin.
To lead astray; to seduce (as under promise of marriage) and then abandon.